+1 There are nice All-in-Ones, for instance the Lenovo A720

> Don't know how anyone can do development solely on a laptop.

Mmmm... I work exclusively on an 11" MacBook Air with no external display. My coworkers think I'm a crazy person, but the constraints work for me. I stay focussed on the one thing that's on screen.

You can do development on a laptop just fine if you plug in an external keyboard and one or two external monitors.